1. Make too low an estimate (9)
6. Fastens securely (5)
9. Vacation (7)
10. Penitence (7)
11. Abundant (7)
12. Porridge (7)
13. Unaggressive (9)
15. A peninsula in northeastern Egypt (5)
16. France's longest river (5)
19. Uncorrupted (9)
22. Sometimes, it's whipped cream (7)
23. Flight attendant (7)
25. Swagger (7)
26. An implement (7)
27. Hebrew unit of dry measure (5)
28. Matter (9)
Down
1. Wedding helper (5)
2. Quandary (7)
3. Shine (7)
4. Heretofore (2 words) (5)
5. Workers (9)
6. Durations (7)
7. A flask for carrying water (7)
8. Fascinate (9)
13. Acceptable to the taste (9)
14. Belonging to the middle class (9)
17. Level a charge against (7)
18. An inscription on a tombstone (7)
20. Gorge (7)
21. Go-between (7)
23. Young pigeon (5)
24. Dig (5)